The Oncopanel Pilot (TOP) Study

Somatic mutations in solid tumors represent an established means of characterizing malignancies for prognostic, diagnostic and therapeutic purposes. Mutations in EGFR, KRAS, BRAF, and KIT and PDGFRA genes direct therapy in patients with advanced lung, colorectal, melanoma, and GIST tumors, respectively. Known or novel mutations in other genes may also be of clinical significance but are not identified by current genotyping offered to BC Cancer Agency (BCCA) patients. Furthermore, numerous candidate genes have been implicated as potential prognostic and predictive biomarkers in patients with solid tumours. As such, the Oncopanel is a clinical assay being developed to determine genotype status of a prospectively defined set of genes. The following clinically relevant set of genes and exons are included in the Oncpanel: KRAS, EGFR, BRAF, NRAS and HRAS, PIK3CA Signal Transduction Pathway Genes, RAS-RAF-MEK-MAPK Pathway, HER2, IDH1 and IDH2, ALK, TP53, c-KIT, STAT1&3 and PDGFRA. Additional testing on the tumour material will also include analysis of specific gene variants associated with adverse events or response to therapy.

Numerous studies have documented the presence of circulating tumour DNA (ctDNA) among patients with advanced and early stage malignancies (20-22). The ability to diagnose standard cancer mutations with a blood-based assay (a "liquid biopsy") has not yet been established but presents obvious advantages. The emergence of "resistance" mutations arising in the metastatic tumor or throughout the course of therapy is well documented (21, 22). A blood biopsy may represent more accurate determination of the tumor's genetic features than archival DNA specimen. Adequate tissue specimens can be difficult to obtain from some patients with diagnosed malignancies, particularly lung cancer. A blood biopsy may represent a less invasive and timelier means of diagnosing both standard and translational cancer mutations.

Patients with archival tumor tissue and a known history of invasive malignancies are eligible if they meet one or more of the following criteria:

• Advanced colorectal cancer and eligible for standard KRAS testing,
• Advanced non-small cell lung cancer and eligible for standard EGFR testing,
• Advanced melanoma and eligible for standard BRAF testing,
• Gastrointestinal stromal tumors (GISTs) eligible for standard c-KIT and PDGFRA testing,
• Being considered for potential eligibility in clinical trial.